1. Field of the Invention
The present invention relates to a disk player, which is used for reproducing, recording or eliminating data on an optical disk, such as DVD-RW, or a magnetic disk (hereinafter referred to as a disk), and it also relates to a worm mechanism for such a disk player. More specifically, the present invention relates to an improvement of a disk player and a worm mechanism for the same, where such a disk is loaded into the disk player by applying a pushing force to a tray for the disk.
2. Description of the Related Art
Such a disk player is equipped with a loading mechanism, which permits loading a disk thereinto in order to reproduce data from the disk or to record data in the disk as well as to discharge the loaded disk therefrom. The loading mechanism includes three different driving mechanisms; a first driving mechanism is used to move a tray on which the disk is placed in the forward or backward direction (discharge direction and load direction) relative to a housing; a second driving mechanism serves to incline in the upward or downward direction a drive chassis onto which a turn table for rotating the loaded disk and an optical pick-up for reading the information in the disk; and a third driving mechanism is used to move the optical pick-up on the drive chassis in the forward or backward direction. In the first driving mechanism, there is a tray detecting unit for determining whether or not the tray resides at the farthest advanced position (the initial position at which the disk is mounted onto the tray), and the detection signal from the tray detecting unit is used to detect the end of the discharge process, and then used to determine the subsequent start of the loading process. By utilizing the second driving mechanism, the drive chassis may be moved from a lower inclined attitude to the horizontal attitude in synchronization with the translational movement of the tray, when the tray is moved from the discharge position onto the turn table at the normal loading position. Furthermore, the third driving mechanism is used to move the optical pick-up to a predetermined read/write position on the drive chassis, after it confirms that the disk is mounted at the normal loading position.
At present, there are two types of disk player prevailingly used. The first type of disk player includes two rotary driving sources (motors). In this case, the first rotary driving source is used to actuate the first, second and third driving mechanisms, whereas the second rotary driving source is connected to a spindle for the turn table, and it is used to rotate the disk. On the other hand, the second type of disk player includes three rotary driving sources. In this case, the first rotary driving source is used to actuate the first driving mechanism, and the second rotary driving source is used to actuate both the second and third driving mechanisms, and the third rotary driving mechanism is connected to a spindle for the turn table, and it is used to rotate the disk, as similarly to the first type of disk player.
In both types of disk player, the rotary movement from the first rotary driving source is transmitted to the first driving mechanism via a worm mechanism having a worm gear and a worm wheel, and finally to a pinion in the first driving mechanism. A rack for the pinion is fixed to the tray, and the rotary movement of the pinion from the first driving source is transformed to a translational movement, so that the tray is moved in the forward or backward direction, as described for a worm mechanism in the first type of disk player in Japanese Unexamined Patent Application Publication No. 2000-54431.
Either in the first type of disk player or in the second type of disk player, a disk is placed on the tray at the farthest advanced position, i.e., the disk-mounting position, and then the first driving mechanism allows the tray to automatically move in the loading position, i.e., the disk-operating position, when the tray is pushed toward the inside of the disk player by one or more fingers of a user. In such a conventional disk player, users sometimes encountered a trouble that the tray was not moved any longer to the loading position, even when the tray was pushed by their finger. The trouble results from the following reasons: The force of pushing the tray arrives at the worm gear in the worm mechanism via the first driving mechanism, and further it is transmitted to the rotary shaft of a motor (the first rotary driving source), which shaft is connected to the worm gear. In this case, the pushing force provides a partial force perpendicular to the axis of the rotary shaft at the worm gear, and such a partial vertical force is applied to bearings in the motor. This causes the motor to stop (that is, self-lock of the motor), and thereby a further movement of the tray to be suppressed.